Reports of Liver Injury Prompt FDA Review of Diet Drug

WASHINGTON -- The FDA said it has received 32 reports of serious liver injury -- including six cases of liver failure -- among users of diet drug orlistat, which is sold as a prescription drug under the trade name Xenical and as an over-the-counter diet aid under the name Alli.

As a result of those reports, the FDA said it had initiated a safety review of the product, which works by blocking the absorption of ingested dietary fats.

Orlistat 120 mg (Xenical) was approved in 1999 for weight loss in conjunction with a reduced caloric diet and for prevention of rebound weight gain after weight loss. The OTC version, orlistat 60 mg, was approved in 2007 for use by overweight adults ages 18 and older.

The FDA said the drug is currently approved for marketing in 100 countries worldwide.

Thirty of the 32 cases of severe liver injury occurred in patients outside the U.S. The most common symptoms were jaundice, weakness, and abdominal pain. Twenty-seven of the 32 patients required hospitalization.

The FDA said that in addition to the 32 reported cases, orlistat safety "was discussed at the CDER Drug Safety Oversight Board in April 2009, and the FDA is reviewing other data on suspected cases of liver injury submitted by the manufacturers of orlistat. FDA's analysis of these data is ongoing and no definite association between liver injury and orlistat has been established at this time."

FDA said it "is not advising healthcare professionals to change their prescribing practices with orlistat. Consumers currently taking Xenical should continue to take it as prescribed, and those using over-the-counter Alli should continue to use the product as directed."

But the FDA advised orlistat users to "consult their healthcare professional if they are experiencing symptoms possibly associated with the use of orlistat and development of liver injury, particularly weakness or fatigue, fever, jaundice, or brown urine. Other symptoms may include abdominal pain, nausea, vomiting, light-colored stools, itching, or loss of appetite."

Asked for a comment about the FDA's announcement, Terry Hurley, a spokesperson for orlistat's maker, Roche, said "patient safety is very important to us. At this time, per the FDA's alert, no causal relationship can be established and changes in prescribing are not recommended."